In this sub-section of our concrete walls chapter, we offer information on successfully installing wire trellises into thin, concrete surfaces (specifically, those under 8cm thick.) You will deal with such walls usually in pre-fabricated garages, partition walls of community high-rise balconies, garden walls, and European rubbish cubicles. The outer shells of pre-fabricated buildings, especially in East Germany, are discussed separately under Weather Shells (double-wall masonry).
The main feature of these structures is that they are almost never recognisable as concrete. For example, with pre-fabricated garages, the very smooth concrete walls are often painted with a granular, neutral colour, to give the effect of having been plastered. Alternatively, the walls can also be made of dyed material, painted in strong colours, stoned, or tiled. This is often referred to as 'lightweight concrete' (see below). Be sure to correctly identify the material of your wall surface before attaching the trellis. Weather shells for pre-fabricated buildings are much less resilient and are therefore discussed separately.
When a wall's thickness drops below 7cm, there is a risk of drilling right through the wall; anything less than 6cm and any rawplugs you choose to insert will protrude, but this can be easily remedied by either trimming the plug so it lies flush with the wall, or replacing it altogether with our small holders-- WM 06093 secured with composite mortar.
For heavier plant loads, we recommend our medium construction "classic” kits, but in conjunction with the cross support WM 10081, which includes a brass rawl plug that will provide extra support. Please include a note in your oder stating any specific requirements.
Due to the shallow drilling depth of only 3.5cm, hitting rebar is very unlikely. In lightweight concrete with lower tensile strength, the cross support WM 10101 is cemented at a depth of about 6cm. In exceptional cases, if a significantly wide gap is needed between the trellis and wall, for example, one of our heavier construction brackets can be used- such as the standard bracket WM 12191 which penetrates the whole wall and is fastened on the other side (see variant 03), or WM 12227 modified as WM 12167 with brass plug. To reduce strain, use 3mm wire rope and when drilling: the hole's diameter should be gradually increased, i.e., in the sequence 6/8/10mm. Please note our tips for drilling holes in concrete!